"America’s ICBM force is a visible reminder that America is prepared to protect itself and its allies from any nation that wishes to harm us," said Enzi, who co-founded and chairs the Senate's bipartisan ICBM Coalition. "This administration’s tendency to arbitrarily and unilaterally reduce our nuclear force only increases threats to our national security."

Enzi has introduced two amendments to protect ICBMs. The first, supported by all members of the coalition, would prohibit the Defense Department from removing ballistic missile silos containing a deployed missile, and requires missiles to be kept at least in a "warm" status.

The second, co-sponsored by fellow Wyoming Sen. John Barrasso and North Dakota Sen. John Hoeven, both Republicans, calls for any further reductions in the nation's nuclear force to be made through the formal treaty-making process outlined in the Constitution.

The moves come as protests stack up against plans by Defense Secretary Chuck Hagel to conduct an environmental-impact study on the possible elimination of ICBM silos.

A timeline prepared by Hagel's office would eliminate one unidentified ICBM squadron and destroy its silos by Dec. 5, 2017, reports The Washington Free Beacon, in order to "meet the New START Treaty compliance date."

According to the timeline, the military would start removing the missiles in October, after the proposed environmental assessment is finished. After that, the silo elimination would start in May 2016, taking 19 months to finish, The Beacon reports.

The United States has 450 Minuteman III missiles at three bases, one each in Wyoming, Montana and North Dakota. Montana Sens. Max Baucus and Jon Tester, both Democrats, also have expressed their concerns at any cuts.

The ICBM Coalition sent a scathing letter to Hagel in September, arguing that the Defense Department needs to determine how many submarine-launched missiles, bombers, and land-based missiles it wants under the federal New START before conducting any study related to eliminating ICBM silos.

"Our letter makes it clear that environmental studies should not dictate our nuclear force posture," Hoeven said. “That is why I included language in the 2014 Defense Appropriations bill that prohibits funding for this study.”

The Senate Appropriations Committee already has agreed to an amendment authored by Hoeven to prohibit the Defense Department from funding the study in 2014. The House approved a similar provision in its version of the 2014 defense appropriations bill.

The senators say that the pending legislation prohibits DOD from spending funds from Fiscal Year 2014 to conduct the study.

Enzi said Thursday that the Obama administration's views on disarmament should come as no surprise.

"We’ve seen President Obama promise to do all that he can to reduce our nuclear arsenal — step by step," said Enzi. "He rammed the New START Treaty through the Senate by promising commitments that he ultimately did not keep. One of those was the promise to modernize our nuclear force, which we’re still waiting on."

"I voted against ratification of the New START Treaty because I believe maintaining a strong nuclear force is a critical part of protecting our country."